1. Field of the Invention
This invention relates to a device for implanting an artificial endosseous element of ceramics in the fields of dentistry, oral surgery and orthopedics, and to a method for implanting such device.
2. Description of the Prior Art
In accordance with the recent trand of development of bio-engineering, implantation of artificial bio-material into the bone tissue of a living body has become popular. For instance, a dental implantation technique has been developed, wherein in order to compensate for the loss of natural teeth, an artificial tooth or implant is implanted or inserted in the endosseous or subperiosteal portion of the jaw as a substitute for a clasp abutment tooth of a cantilevered bridge or an abutment tooth of a fixed bridge. The artificial tooth or teeth thus implanted by the implantation technique is called an implant crown, an implant bridge or an implant denture.
As for the type of the endosseous implant in the fields of dentistry and oral surgery, the pin, blade and screw variety is well known. A screw implant has, on the circumference of an implant screw pin (i.sub.0), as shown in FIGS. 5 and 6, a screw (10) for threading into a jaw bone (b). The implant screw pin (i.sub.0) is screwed in a tapped hole (50) provided in the jaw bone. The tapped hole (50) can readily be made to correspond to the screw (10) to be implanted in the jaw bone (b). After the implant screw pin (i.sub.0) is implanted in the jaw bone (b), an artificial tooth (t) is fixed to an upper portion (20) of the implant screw pin (i.sub.0) by means of an adhesive compound (40). Since the formation of the tapped hole in the bone tissue may cause some destruction of the bone tissue or pain to the patient, the pitch of the thread in the tapped hole (50) is designed to be comparatively large. In response thereto the pitch of the screw (10) of the implant screw pin (i.sub.0) is made large.
Accordingly, when the implant screw pin (i.sub.0) is screwed in the bone structure, a substantial clearance is formed between the screw (10) and the tapped hole (50) and under these conditions, if repeated biting stress is concentrated to a lower portion (t.sub.2) of the artificial tooth (t) connected to a portion (20) (tool-attaching portion) above the implant screw pin (i.sub.0), the connection between the implant screw pin (i.sub.0) and the jaw bone (b) may become loose. The implant screw pin (i.sub.0) may then become infirm or unstable, and a pocket (p) may be formed between the gingival tissue and the implant screw pin (i.sub.0). This condition may not only prevent the growth of the tissues surrounding the implant screw pin (i.sub.0), but also it may cause some bone atrophy. The pocket (p) may become enlarged as a result of bone atrophy, whereupon the implant screw pin (i.sub.0) becomes more unstable even to the point of causing the implant screw pin (i.sub.0) to drop out of hole (50) thus reducing the pocket (p) to a nest of bacilli which will infect the patient.